Elsevier

Heart Rhythm

Volume 8, Issue 10, October 2011, Pages 1608-1614
Heart Rhythm

Regular issue
Clinical: Ablation
Reversal of outflow tract ventricular premature depolarization–induced cardiomyopathy with ablation: Effect of residual arrhythmia burden and preexisting cardiomyopathy on outcome

https://doi.org/10.1016/j.hrthm.2011.04.026Get rights and content

Background

Outflow tract ventricular premature depolarizations (VPDs) can be associated with reversible left ventricular cardiomyopathy (LVCM). Limited data exist regarding the outcome after ablation of outflow tract VPDs from the LV and the impact of residual VPDs or preexisting LVCM prior to the diagnosis of VPDs on recovery of LV function.

Objective

To examine the safety, efficacy, and long-term effect of radiofrequency ablation on LV function in patients with LVCM and frequent outflow tract VPDs and examine the effect of ablation in patients with LVCM known to precede the onset of VPDs and the impact of residual VPD frequency on recovery of LV function.

Methods

Sixty-nine patients (43 men; age 51 ± 16 years) with nonischemic LVCM (left ventricular ejection fraction [LVEF] 35% ± 9%, left ventricular diastolic diameter [LVDD] 5.8 ± 0.7 cm) were referred for ablation of frequent outflow tract VPDs (29% ± 13%).

Results

VPDs originated in the right ventricular outflow tract in 27 (39%) patients and the left ventricular outflow tract in 42 (61%) patients. After follow-up of 11 ± 6 months, 44 (66%) patients had rare (<2%) VPDs, 15 (22%) had decreased VPD burden (>80% reduction and always <5000 VPDs), and 8 (12%) had no clinical improvement with persistent (5 patients) or recurrent (3 patients) VPDs. Only patients with either rare or decreased VPD burden had a significant improvement in LVEF (ΔLVEF 14% ± 9% vs 13% ± 7% vs –3% ± 6%, respectively, P <.001) and LVDD (ΔLVDD –4 ± 5 vs –2 ± 4 vs 0 ± 4, respectively, P = .038), regardless of chamber of origin. The magnitude of LVEF improvement correlated with the decline in residual VPD burden (r = 0.475, P = .007). Patients with preexisting LVCM had a more modest but still significant improvement in LV function compared to patients without preexisting LVCM (ΔLVEF 8% vs 13%, P = .046). Multivariate analysis revealed ablation outcome, higher LVEF, and absence of preexisting LVCM were independently associated with LVEF improvement.

Conclusion

Frequent outflow tract VPDs are associated with LVCM regardless of ventricle of origin. Significant (>80%) reduction in VPD burden has comparable improvement in LV function to complete VPD elimination. Successful VPD ablation may be beneficial even in patients with preexisting LVCM.

Introduction

Ventricular premature depolarizations (VPDs) originating from the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT) are frequently encountered in clinical practice. Although they occur mostly in patients without structural heart disease, they have been described in the setting of left ventricular cardiomyopathy (LVCM). A few small series have shown that successful ablation of VPDs originating from the RVOT can result in resolution of LVCM, suggesting causality between frequent VPDs and the development of LVCM.1, 2, 3 Despite these seminal observations, limited data exist regarding an association between VPDs from the LVOT and LVCM as well as outcome with ablation in those patients. The impact of residual VPDs or preexisting LVCM on the recovery of LV function after VPD ablation is also unknown.3, 4

The purpose of this study was to examine the safety, efficacy, and long-term effect on LV function of radiofrequency ablation in a relatively large patient population with LVCM and frequent VPDs originating from the RVOT and LVOT. In addition, we sought to examine the long-term effect of ablation in patients with LVCM known to precede the onset of VPDs and the impact of residual VPD frequency on recovery of LV function.

Section snippets

Inclusion criteria

We retrospectively analyzed 69 consecutive patients with frequent VPDs (>5,000 VPDs per 24 hours) and LVCM, defined as left ventricular ejection fraction (LVEF) <50% referred to our institution for catheter ablation. The predominant VPDs were required to have ECG characteristics suggestive of outflow tract origin (right or left bundle branch morphology, inferior axis, negative in lead aVL). Active ischemia or prior infarction as a cause of cardiomyopathy was ruled out in all cases by history,

Patient characteristics

Of 317 consecutive patients undergoing ablation of outflow tract VPDs at our institution, 69 had LVCM (43 men; mean age 51 ± 16 years) and are the focus of the present investigation. Fifty-two (75%) of the patients had symptomatic VPDs with palpitations, and 17 (25%) patients were referred for ablation of frequent asymptomatic VPDs in the setting of cardiomyopathy. All patients had >5,000 VPDs on 24-hr Holter monitoring (mean 31,975 ± 16,918 [29% ± 13%]). Nineteen (28%) patients had more than

Discussion

We describe the largest series of patients undergoing ablation with RVOT and/or LVOT VPDs and LVCM. Our patients were on stable maximally tolerated medical therapy for treatment of LVCM for at least 6 months prior to ablation. As such, initiation of medical therapy is unlikely to explain the improvement in LVEF observed following ablation. In addition, by using echocardiograms obtained the day postablation, we minimized the uncertainties of LVEF measurement in the setting of frequent ectopy.

The

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